Large-scale production of high-efficiency solar cells plays an important role in ensuring the success of solar power over conventional energy sources that are based on fossil fuels. However, most of the current processes for manufacturing high-efficiency solar cells are not optimized for mass production. For example, many laboratory-made solar cells demonstrate superior performance, but the fabrication process for those solar cells cannot be applied in a mass production environment.
It has been shown that double-junction heterojunction solar cells can demonstrate higher efficiency than single-junction solar cells. However, mass production of double-junction solar cells can be challenging, because the double-junction structure can require excellent surface passivation on both surfaces of the crystalline Si substrates, whereas the current fabrication process often leads to contamination on one side of the solar cells.